Almost half (45 percent) of all adolescents studied were trying to lose weight, even if they didn’t need to. One in five tried unhealthy means such as fasting or laxatives. On the other hand, teenagers who correctly understood what their weight should be were more likely to try healthy weight loss methods such as improving diet and physical activity.

But there was a gap between perception and reality of who’s overweight. Less than a third (29.3 percent) of adolescents thought they were overweight. Girls were more likely to believe that they were overweight (35.4 percent) than boys (23.7 percent). Ironically, 32.1 percent of boys and 24.2 percent of girls were actually overweight.

“We found high and persistent prevalence of weight misperception among ninth through 12th grade U.S. schoolchildren. What is even more disconcerting is the high rate of overweight status in adolescents nationwide. The associated misperception is a hindrance to all interventions aimed at reducing childhood obesity,” said study co-author Maoyong Fan, a professor in Ball State’s Department of Economics.

Misperception of weight varied by race. Black females were least likely to believe they were overweight even if they were (37.5 percent of black females were actually overweight, but only 30.9 percent thought they were overweight).

Teenagers who had a poor grades were less likely to have correct weight perception.

Adolescents with depressive symptoms and prior suicide attempts were more likely to believe they were overweight and try dangerous methods of weight loss.

“Childhood obesity is a complex issue. In addition to actual body weight of children, self-perception of weight should also be considered while planning activities to reduce childhood obesity. This study provides insights that are meaningful for tailored prevention interventions that could address prevalence of obesity, weight misperception and unhealthy weight control practices,” Khubchandani said.